Patent Application
20250074082
The entire disclosure of Japanese Patent Application No. 2023-141669, filed on Aug. 31, 2023. including description, claims, drawings and abstract is incorporated herein by reference.
The present invention relates to an inkjet recording apparatus and an inkjet recording method.
Conventionally, inkjet recording apparatuses that record an image by ejecting ink onto a recording surface of a recording medium have been known. In particular, in-line inkjet recording apparatuses are known that eject a pretreatment liquid during conveyance of the recording medium.
However, as a result of ejecting an excessive amount of the pretreatment liquid onto the recording medium, the recording medium may absorb and expand to cause lifting wrinkles. Then, when the head of the inkjet recording apparatus comes into contact with the lifting wrinkle, an image forming defect may occur.
Therefore, for example, Japanese Unexamined Patent Publication No. 2015-110275 describes an inkjet recording apparatus in which a light interruption sensor is provided on an upstream side of a conveyance apparatus. and in a case where lifting of a recording medium is detected, image formation is temporarily interrupted and a warning is issued.
However, in the inkjet recording apparatus of Japanese Unexamined Patent Publication No. 2015-110275, it is not possible to detect the lifting wrinkle generated by ejecting the pre-processing liquid. In addition, it is not possible to suppress defects caused by the application of the pretreatment liquid, not limited to the lifting wrinkles.
Similarly, in a case where the post-treatment liquid is ejected by the in-line method after the ink is ejected onto the recording medium, the head for the post-treatment liquid may come into contact with the lifting wrinkles generated by the ejection of the ink. However, in the inkjet recording apparatus of Japanese Unexamined Patent Publication No. 2015-110275, such a problem could not be suppressed.
The present invention has been made in view of such circumstances. It is an object of the present invention to provide an inkjet recording apparatus and an inkjet recording method that can suppress failures caused by in-line application of a first liquid such as a pretreatment liquid.
In order to solve the above problem, an inkjet recording apparatus includes a conveyor that conveys a recording medium, an image former that forms an image on the recording medium; and a detector that detects a state of the recording medium, wherein, the image former includes, a first ejection head that ejects a first liquid onto the recording medium, and a second ejection head that ejects a second liquid onto the recording medium, and the detector detects a state of the recording medium after the first liquid is ejected by the first ejection head and before the second liquid is ejected by the second ejection head.
According to another aspect, an inkjet recording method of an inkjet recording apparatus, the inkjet recording apparatus including, a first ejection head that ejects a first liquid onto a recording medium, and a second ejection head that ejects a second liquid onto the recording medium, the inkjet recording method comprising: conveying the recording medium; forming an image on the recording medium; and detecting a state of the recording medium, wherein in the detecting, a state of the recording medium after the first liquid is ejected by the first ejection head and before the second liquid is ejected by the second ejection head is detected.
The advantages and features provided by one or more embodiments of the invention will become more fully understood from the detailed description given hereinafter and the appended drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein:
Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments.
Hereinafter, an inkjet recording apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. In the following description, components having the same functions and configurations are denoted by the same reference numerals, and the description thereof will be omitted.
Note that hereinafter, an X direction, a Y direction, and a Z direction refer to the directions illustrated in
The conveyance section 2 conveys a recording medium M in the conveyance direction so as to pass below the image forming section 3. The conveyance section 2 includes, for example, two conveyance rollers 2a and 2b that rotate in the conveyance direction around rotation shafts extending in a widthwise direction. Furthermore, the conveyance section 2 includes a ring-shaped conveyance belt 2c.
The inner side of the conveyance belt 2c is supported by the conveyance rollers 2a and 2b. In addition, an adhesive is applied to a conveyance surface of the conveyance belt 2c, which is a surface different from an inner surface that comes into contact with the conveyance rollers 2a and 2b and is an outer surface on a side on which the recording medium M is placed. The recording medium M is placed on the conveyance surface of the conveyance belt 2c. The conveyance rollers 2a and 2b rotate and circulate in the conveyance direction in accordance with an operation of a conveyance motor of the roller. As a result, the conveyance belt 2c conveys the recording medium M in the conveyance direction.
The recording medium M is, for example, fabric. The recording medium M is supplied onto the conveyance belt 2c by a medium supply section (not shown). An image is recorded on the recording medium M by ink ejected from the image forming section 3. The recording medium M on which the image is recorded is discharged to a discharge section (not shown). Note that the recording medium M is not limited to fabric. The recording medium M may be any recording medium on which landed ink can be fixed, and may be any of various media such as paper.
In the case where the recording medium M is a fabric, if the fabric is a thin cloth having a thickness of 0.4 mm or less or a basis weight of 90 g/m2 or less, or if the fabric is made from cotton or polyester, lifting wrinkles are likely to occur due to excessive application of the pre-treatment liquid described later. Usually, image formation failure occurs when the image is formed with the lifting wrinkle formed on the recording medium M, but the inkjet recording apparatus 1 according to the present embodiment can detect the lifting wrinkles before image formation.
The image forming section 3 forms the image by ejecting the ink onto the recording medium M conveyed by the conveyance section 2 at an appropriate timing based on image data acquired from an external device or the like.
The carriage 31 is a member that moves the mounted head unit 32. The carriage 31 includes, for example, a belt bridged between two pulleys that are rotated by a motor (not illustrated). The carriage 31 causes the head unit 32 to scan in the width direction by a rotating operation of the motor based on a drive signal output by the controller 8. Furthermore, the pulley and the belt are extended further to the outside than a conveyance path along which the recording medium M is conveyed. Therefore, the carriage 31 is movable further outward than the conveyance path of the recording medium M.
The inkjet recording apparatus 1 according to the present embodiment forms the image by ejecting the ink from the head unit 32 while allowing the carriage 31 to scan in the width direction, the carriage 31 being shorter than the recording medium M in length in the width direction. The inkjet recording apparatus 1 may employ a single-pass (one pass) method in which the image is formed by allowing the carriage 31 to scan once, or a multi-pass (scan) method in which an image of one line is formed by allowing the carriage 31 to scan a plurality of times.
The head unit 32 is constituted by a plurality of inkjet heads. Each inkjet head includes an ink tank, a channel, a piezoelectric element, a plurality of nozzles, and the like. Under the control of the controller 8, the head unit 32 causes the piezoelectric element to apply pressure fluctuation to ink supplied from the tank to the nozzle via the channel, thereby ejecting the ink. The inkjet heads constituting the head unit 32 are a first ejection head 32a and a second ejection head 32b.
The first ejection head 32a is an inkjet head that ejects a first liquid onto the recording medium M prior to the second ejection head 32b. In the present embodiment, the first liquid is the pretreatment liquid containing an aggregating agent. As illustrated in
The pre-treatment liquid ejected from the first ejection head 32a is mixed in liquid form with the second liquid ejected from the second ejection head 32b on the recording medium M. The pretreatment liquid contains at least the aggregating agent. The pretreatment liquid may further contain other components such as a solvent, a surfactant, and water. The aggregating agent contained in the pretreatment liquid is not particularly limited as long as it generates an aggregate when coming into contact with the second liquid, and examples thereof include a polyvalent metal salt, an organic acid, and an inorganic acid.
The second ejection head 32b ejects the second liquid after the first ejection head 32a ejects the pre-treatment liquid that is the first liquid. In the present embodiment, the second liquid is colored ink. As illustrated in
The colored ink ejected by the second ejection head 32b is, for example, pigment ink. The pigment ink is an ink containing a pigment, resin particles (binder resin), and water. When the pigment ink is applied to the recording medium M on which the pretreatment liquid has been applied, the components contained in the pigment ink do not penetrate into the recording medium M, the color developability increases, and the texture is less likely to be impaired. In addition, unlike dye ink, the pigment ink does not require heating treatment for dyeing and treatment for washing away undyed dye.
The liquid receiving section 41 receives liquid (pre-treatment liquid and colored ink) ejected from the head unit 32. In the liquid receiving section 41, an absorber such as a sponge having hydrophilicity is stored. The liquid receiving section 41 discharges, from a discharge port provided in a bottom surface portion or the like, the liquid ejected and received from the head unit 32. The liquid receiving section 41 includes a discard tub 41a and a maintenance tub 41b.
The discard tub 41a is provided closer to the conveyance path of the recording medium M than the maintenance tub 41b. The length of the discard tub 41a in the width direction is slightly larger than one nozzle row in one inkjet head.
The controller 8 causes the discard tub 41a to execute a discarding ejection of the ink every time the carriage 31 scans. The control can prevent the liquids (the pretreatment liquid and the colored ink) in each inkjet head from drying and thickening in the nozzles.
In
The maintenance tub 41b is provided farther from the conveyance path of the recording medium M than the discard tub 41a. The maintenance tub 41b is provided so as to be slightly wider than the carriage 31 in the widthwise direction.
In a case where normal pressure is not applied to the ink and the ink is not ejected from the nozzles of each inkjet head and an image defect occurs (in a case where a so-called nozzle clogging phenomenon occurs), the controller 8 conveys the carriage 31 above the maintenance tub 41b and causes purging to be executed. Specifically, in order to eject foreign matters, air bubbles, aggregates, and the like in each inkjet head to the outside, the controller 8 increases the supply pressure of the ink to each inkjet head to forcibly eject the ink.
Note that the amount of ink ejected by purging is greater than the amount of ink ejected by discard ejection. Therefore, as shown in
The cleaning section 42 is provided in the vicinity of the maintenance tub 41b, and wipes an ink ejection face of the head unit 32 after purging with a wiping cloth or the like. The cleaning section 42 includes a wiping cloth and a moving mechanism that moves the wiping cloth along the ink ejection face of the head unit 32. The wiping operation of the cleaning section 42 can remove ink, foreign matter, and the like adhered to the ink ejection face of the head unit 32 during purging.
The moisturizing section 43 is a container in which a predetermined liquid such as water is accommodated and the nozzle surface side of the image forming section 3 is opened. The liquid contained in the moisturizing section 43 is evaporated to humidify the nozzles of the head unit 32 when not in use, thereby preventing the nozzles from being clogged.
The detecting section 5 detects a state of the recording medium M, in particular, lifting of the recording medium M from a reference surface B. The detecting section 5 is, for example, a light interruption sensor. The detecting section 5 includes a light emitter 51a and a light receiver 51b. The light emitter 51a emits a linear laser beam having a predetermined width in a height direction. The light receiver 51b receives the laser beam emitted by the light emitter 51a.
As shown in
The detecting section 5 detects a lifting wrinkle of the recording medium M during image formation by the image forming section 3, To be specific, the light receiver 51b detects the light blocking, that is, the generation of the lifting wrinkle when the lifting of the recording medium M becomes equal to or more than a predetermined threshold value, for example, a length between the second ejection head 32b and the reference surface B, and the amount of light acquired from the light emitter 51a decreases by a predetermined value or more. The light receiver 51b that has detected the occurrence of the lifting wrinkle transmits a signal to the controller 8. Upon receiving the signal, the controller 8 causes the image forming section 3 to stop the image forming operation and causes the notifying section 6 to issue a warning.
Note that the position of the detecting section 5 in the height direction is adjustable. Therefore, the reference surface B can be appropriately set in accordance with the thickness or the like of the recording medium M. In
Further, in the present embodiment, as shown in
When the discharge port of the discard tub 41a or the maintenance tub 41b is clogged, the color ink and the pretreatment liquid may be mixed. In this case, the color ink and the pretreatment liquid may be aggregated in the discard tub 41a or the maintenance tub 41b to form the aggregate. Then, the aggregate that has reached the predetermined height and the head unit 32 may come into contact with each other, resulting in damage to the head unit 32.
However, with the above-described arrangement, the light receiver 51b transmits the signal to the controller 8 also in a case where the height of the aggregate in the discard tub 41a or the maintenance tub 41b is, for example, greater than or equal to the distance between the second ejection head 32b and the discard tub 41a or the maintenance tub 41b. Therefore, damage to the head unit 32 due to contact between the aggregate and the head unit 32 can be prevented.
The notifying section 6 provides notification of various information under the control of the controller 8. The notifying section 6 is, for example, a display part having a screen, a sound emitting section that emits a predetermined sound, a communication section that can communicate with another device via a network, or the like.
The operation input section 7 is composed of, for example, various operation keys and the like, converts a user's input operation into an operation signal, and outputs the operation signal to the controller 8. Note that when the notifying section 6 is a display part, the operation input section 7 may be a touch screen.
The controller 8 (hardware processor) includes a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM). Thus, the controller 8 controls the overall operation of the inkjet recording apparatus 1.
The CPU controls each part of the inkjet recording apparatus 1. The RAM is a volatile memory that temporarily stores various kinds of information in a writable and readable manner. The ROM is a non-volatile memory in which various types of information and programs are stored in a readable manner. More specifically, the controller 8 causes the CPU to read a specified program from various programs stored in the ROM and load the program into the RAM. Then, the controller 8 executes various kinds of processing in coordination with the loaded program.
In particular, the controller 8 functions as an image formation controller that controls whether to cause the image forming section 3 to form an image in accordance with a detection result of the detecting section 5. The controller 8 also functions as a notification controller that causes the notifying section 6 to issue the warning in accordance with the detection result of the detecting section 5.
Image forming processing in such an inkjet recording apparatus I will be described with reference to the flowchart of
First, the controller 8 determines whether or not the detecting section 5 has detected lifting (light blocking) (step S101). When the detecting section 5 detects lifting (step S101; Yes), the controller 8 serving as a notification controller causes the notifying section 6 to issue the warning (step S102). Further, the controller 8 serving as the image forming controller causes the conveyance section 2 and the image forming section 3 to stop the image forming operation (step S103).
Upon being notified by the notifying section 6, the user smooths out and corrects the lifting wrinkle generated on the recording medium M. Alternatively, the recording medium M is manually conveyed to evacuate the lifting wrinkle to the outside of the printing region. Then, the user adjusts the amount of the pretreatment liquid to be ejected by the first ejection head 32a to be small. Alternatively, the user cleans the discard tub 41a or the maintenance tub 41b. When the processing relating to the lifting wrinkles of the recording medium M or the aggregate in the liquid receiving section 41 is finished, the user transmits an instruction to resume the image forming operation to the controller 8 by operating the operation input section 7.
The controller 8 determines whether an instruction to resume the image forming operation has been acquired (step S104). If the instruction to resume the image forming operation is acquired (step S104; Yes), the controller 8 resumes the image forming operation (step S105), and transitions to step S101 to detect the lifting again.
In a case where the detecting section 5 does not detect lifting (step S101; No), the controller 8 forms an image on the recording medium M by discharging ink from the second ejection head 32b while the carriage 31 performs scanning (step S106). After scanning by the carriage 31, the controller 8 causes the conveyance section 2 to convey the recording medium M by a predetermined amount (step S107).
The controller 8 determines whether the image forming operation has been completed (step S108). In the case where the image forming operation is completed (Step S108; Yes), the controller 8 ends the image forming process. If the image forming operation has not been completed (step S108; No), the controller 8 transitions to step S101.
As described above, the inkjet recording apparatus 1 according to the present embodiment includes the conveyance section 2 to convey the recording medium M. The inkjet recording apparatus 1 further includes an image forming section 3 to form the image on the recording medium M. The inkjet recording apparatus 1 further includes a detecting section 5 to detect the condition of the recording medium M. The image forming section 3 includes the first ejection head 32a that ejects the pretreatment liquid, which is the first liquid, onto the recording medium M. Furthermore, the image forming section 3 includes the second ejection head 32b that ejects ink, which is the second liquid, onto the recording medium M. Then, the detecting section 5 detects the state of the recording medium M after the first ejection head 32a ejects the first liquid and before the second ejection head 32b ejects the second liquid.
With this structure, even if a state occurs in which a failure is caused by the application of the pretreatment liquid by the first ejection head 32a, the state can be suppressed by the detecting section 5 sensing it. In particular, since the detecting section 5 detects lifting of the recording medium M from the reference surface, it is possible to suppress occurrence of image formation failure on the recording medium M.
In the above description, a configuration in which the light interruption sensor which is the detecting section 5 includes only a pair of the light emitter 51a and the light receiver 51b is exemplified, but the invention is not limited thereto. That is, the light interruption sensor including a plurality of sets of light emitters 51a and light receivers 51b corresponding to all the nozzle rows of the head unit 32 may be provided as the detecting section 5. With this configuration, it is possible to further suppress a defect caused by the application of the pretreatment liquid.
Next, an inkjet recording apparatus 1 according to a second embodiment will be described. The same symbols are used for the same configuration as that of the inkjet recording apparatus 1 of the first embodiment, and the detailed description is omitted.
As illustrated in
As described above, even in a case where the detecting section 5 includes the distance meter 52, it is possible to sense and suppress a state in which a problem due to application of the preprocessing liquid by the first ejection head 32a occurs.
Next, the inkjet recording apparatus 1 according to a third embodiment will be described. Note that elements that are the same as those of the inkjet recording apparatus 1 according to the first and second embodiments are denoted by the same reference numerals, and detailed description of those elements is omitted. The inkjet recording apparatus 1 according to the third embodiment is different from the first and second embodiments in that the first liquid ejected from the first ejection head 32a is a colored ink and the second liquid ejected from the second ejection head 32b is a post-treatment liquid.
In the inkjet recording apparatus 1 according to the third embodiment, the post-treatment liquid ejected by the second ejection head 32b is, for example, a colorless coating ink. Even in a case where the first ejection head 32a ejects colored ink, the recording medium M may contract and expand to cause lifting wrinkles. Then, the second ejection head 32b comes into contact with the lifting wrinkle, and a failure such as breakage may occur.
However, in the present invention, as described above, the detecting section 5 is provided which detects the state of the recording medium M after the ejection of the first liquid by the first ejection head 32a and before the second ejection head 32b ejects the second liquid. Therefore, in the inkjet recording apparatus 1 according to the third embodiment, even if a state in which a failure is caused due to ink application by the first ejection head 32a occurs, the state can be suppressed by sensing by the detecting section 5.
Although specific description has been given above based on the embodiment according to the present invention, the present invention is not limited to the above-described embodiment. It is a matter of course that the present invention can be subjected to various modifications within the scope of the invention described in the claims and the equivalents thereof.
For example, in the above description, a configuration in which the detecting section 5 detects lifting of the recording medium M has been exemplified, but the invention is not limited thereto. For example, the detecting section 5 may detect a lump of the first liquid or a fold on the recording medium M. In addition, as the detecting section 5, the light interruption sensor and the distance sensor are exemplified, but a contact sensor or the like may be used.
In addition, in the above description, as shown in
In addition, in the above description, as shown in
As illustrated in
In addition, in the above description, a configuration in which the second liquid discharged by the second ejection head 32b is color ink is exemplified, but the invention is not limited thereto. That is, in the first and second embodiments, the second liquid may be not only color ink but also the pretreatment liquid, in particular, white ink. Specifically, after the pretreatment liquid containing the aggregation agent is ejected from the first ejection head 32a, the white ink may be ejected from the second ejection head 32b on the upstream side in the conveyance direction or the width direction, and the color ink may be ejected from the second ejection head 32b on the downstream side.
In addition, in the above description, the serial type inkjet recording apparatus 1 which forms an image by scanning the carriage 31 of which the length in the width direction is shorter than the recording medium M in the width direction has been exemplified, but the invention is not limited thereto. That is, in the first and third embodiments, the inkjet recording apparatus 1 may be of a line system in which the head unit 32 having a length in the width direction longer than that of the recording medium M forms the image without scanning in the width direction.
Furthermore, in a case where the notifying section 6 includes a display part, the display part may display, in real time, the lifting displacement of the recording medium M from the reference surface B acquired by the detecting section 5.
In addition, in the image forming process, after the image forming operation is stopped in step S103, the user performs the process related to the lifting wrinkles of the recording medium M or the aggregate in the liquid receiving section 41, and instructs the restart of the image forming operation by the operation input section 7, but the invention is not limited thereto. That is, it may be possible to adopt a configuration in which the inkjet recording apparatus 1 is provided with a mechanism capable of executing processing related to the lifting wrinkles of the recording medium M or aggregates in the liquid receiving section 41 and in which, through processing under the control of the controller 8, the image forming operation is automatically resumed when the detecting section 5 no longer detects the lifting.
Although embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are made for purposes of illustration and example only and not limitation. The scope of the present invention should be interpreted by terms of the appended claims.
The entire disclosure of Japanese Patent Application No. 2023-141669, filed on Aug. 31, 2023. including description, claims, drawings and abstract is incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-141669 | Aug 2023 | JP | national |
